A close-up view of the wood cell wall ultrastructure and its mechanics at different cutting angles by atomic force microscopy

摘要: AFM measurements on spruce sample cross-sections reveal that the structural appearance of S2 layer changes from a network structure to concentric lamellar texture depending cutting angle. The assembly wood constituents within secondary cell wall has been subject numerous studies over last decades, which resulted in contradicting models spatial arrangement and orientation macromolecules. Here, we use multichannel atomic force microscopy by means quantitative imaging, gain new insights into macromolecular assembly. Cross-sections wood, had cut at different angles ranging 0° 30° were investigated. Strikingly, angle, changed network-like distinct texture. This makes us conclude often visualized organization is not consequence continuous inherent ring pattern, but rather result specific surface cross-section cellulose aggregates larger angles. By analyzing recorded distance curves every pixel, nano-mechanical characterization was conducted. Substantially lower indentation modulus values obtained compared nanoindentation reported literature. potentially due smaller interaction volume probe with far less deep indentation.